Hi, I've created a group chat for Flock attendees who are using Telegram to communicate and share info: http://bit.ly/flock15tg
We've used it during GUADEC and it turned out to be very popular and useful. Historically, IRC channels are used for this, but considering how many people are using smartphones and that at conferences you often get connected/disconnected, IRC's not ideal. If we have an official IRC channel, there should be a way to sync the channel with the group chat via a Telegram bot, but I haven't had time to look at it. But if someone wants to explore this idea, I'll be happy to add the bot to the chat.
Jiri